In Long Term Evolution (LTE) communications technology, duplex modes may be classified into two types, Frequency Division Duplex (FDD) and Time Division Duplex (TDD). In the FDD mode, different frequencies are used in uplink and downlink channels, and frames of fixed time lengths are used for both uplink transmission and downlink transmission. In the TDD mode, uplink transmission and downlink transmission are performed in different timeslots, and usually share a same frequency. Compared with FDD, TDD has characteristics of high frequency utilization and flexible uplink and downlink resource configuration.
A Carrier Aggregation (CA) technology is a key technology in LTE, and is used to implement aggregation of carriers at two frequencies. Generally, the CA technology may be implemented by using a radio frequency circuit of a terminal. According to different aggregation modes, CA may be classified into three types: intra-band contiguous CA, intra-band non-contiguous CA, and inter-band CA. Usually, the intra-band contiguous CA is applicable to a scenario of narrow frequency spacing, and a radio frequency circuit structure thereof is simple; the intra-band non-contiguous CA and inter-band CA are applicable to a scenario of wide frequency spacing. Since frequency resources vary across global communications markets, the CA technology is evolved with one of its focuses placed on promoting the capability of a radio frequency circuit to support wider frequency spacing.
In the prior art, in the TDD mode, two different bands in inter-band CA are both used to transmit uplink signals or both used to receive downlink signals in a TDD timeslot, and consequently, the uplink and downlink resource configurations are inflexible.